Shutoff system for a container

ABSTRACT

Said closure system comprises a neck element intended to be fastened on the receptacle and comprising a neck portion provided with a retaining collar; a closure cap intended to be removably fastened on the neck portion, the closure cap including a closure wall and a fastening skirt; and a tamper-proof ring connected to the fastening skirt by a plurality of frangible elements, the tamper-proof ring comprising at least one flexible retaining element. The neck portion and the tamper-proof ring are configured such that, in use, the retaining collar defines an annular hooking housing in which the at least one flexible retaining element is adapted to be at least partially received.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of PCT Application No. PCT/EP2016/080919 filed on Dec. 14, 2016, which claims priority to French Patent Application Nos. 15/63042 filed on Dec. 22, 2015 and 16/53875 filed on Apr. 29, 2016, the contents each of which are incorporated herein by reference thereto.

TECHNICAL FIELD

The present invention concerns a closure system for a receptacle.

BACKGROUND

Such a closure system comprises in a known manner:

-   -   a neck element intended to be fastened on the receptacle, the         neck element comprising a neck portion including a retaining         collar provided with a stop surface,     -   a closure cap intended to be fastened by screwing on the neck         portion, the cap including a closure wall and a fastening skirt,         and     -   a tamper-proof ring connected to the fastening skirt by a         plurality of frangible elements, the tamper-proof ring         comprising a plurality of flexible retaining elements configured         to abut against the stop surface of the retaining collar during         unscrewing of the closure cap.

Such a configuration of the retaining collar and the retaining elements allows, during the unscrewing of the closure cap, immobilizing the tamper-proof ring and therefore causing a breakage of the frangible elements connecting the fastening skirt and the tamper-proof ring. Such a breakage of the frangible elements ensures an easy check of any prior opening of a receptacle equipped with the aforementioned closure system.

However, in view of the flexibility of the retaining elements, in rare cases, these may be elastically deformed and bypass the retaining collar during an unscrewing of the closure cap. In such cases, the tamper-proof ring is likely to fall by gravity into a container into which the content of the receptacle equipped with the closure system is intended to be poured, and therefore to be ingested by the consumer.

BRIEF SUMMARY

The present invention aims to overcome this drawback.

The technical problem underlying the invention therefore consists in providing a closure system for a receptacle which has a simple and economical structure, while ensuring a reliable retention of the tamper-proof ring on the neck portion.

To this end, the present invention concerns a closure system for a receptacle, comprising:

-   -   a neck element intended to be fastened on the receptacle, the         neck element comprising a neck portion provided with a retaining         collar which is flexible,     -   a closure cap intended to be screwed on the neck portion, the         closure cap including a closure wall and a fastening skirt, and     -   a tamper-proof ring connected to the fastening skirt by a         plurality of frangible elements, the tamper-proof ring         comprising at least one flexible retaining element, for example         configured to cooperate with the retaining collar,

the neck portion and the tamper-proof ring being configured such that, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, the retaining collar defines an annular hooking housing, and the at least one flexible retaining element is configured to be at least partially received and be hooked into the annular hooking housing,

characterized in that the retaining collar is configured to extend at least partially between the fastening skirt and the tamper-proof ring during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements.

Such a configuration of the retaining collar allows ensuring, during the first opening of a receptacle equipped with the closure system according to the invention, an insertion of the at least one flexible retaining element in the hooking housing and a hooking between the retaining collar and the at least one retaining element. Such a hooking avoids any risk of accidental removal of the tamper-proof ring, and thus ensures a reliable retention of the tamper-proof ring on the neck portion.

Furthermore, such an extension of the retaining collar between the fastening skirt and the tamper-proof ring, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, ensures an easy check of a prior opening of a receptacle equipped with the closure system according to the invention.

The closure system may further have one or more of the following features, considered alone or in combination.

According to an embodiment of the invention, the tamper-proof ring is intended to be mounted on the neck portion.

According to an embodiment of the invention, the neck portion and the tamper-proof ring are configured such that the retaining collar defines an annular hooking housing at least until the first screwing back of the closure cap on the neck portion after breakage of the frangible elements.

According to an embodiment of the invention, the retaining collar is deformable, for example elastically or plastically, between an initial position in which the retaining collar extends substantially radially relative to an extension axis of the neck portion, and a retaining position in which the retaining collar is curved and delimits the annular hooking housing.

According to an embodiment of the invention, the tamper-proof ring is configured to deform and hold the retaining collar in its retaining position at least until the breakage of the frangible elements, and for example at least until the first screwing back of the closure cap on the neck portion after breakage of the frangible elements.

According to an embodiment of the invention, the tamper-proof ring is configured to extend around the retaining collar at least until the breakage of the frangible elements, and for example at least until the first screwing back of the closure cap on the neck portion after breakage of the frangible elements.

According to an embodiment of the invention, the retaining collar comprises a hooking surface configured to define the hooking housing. Advantageously, the hooking surface is curved at least until the breakage of the frangible elements.

According to an embodiment of the invention, the at least one flexible retaining element has a first surface configured to cooperate with the outer surface of the neck portion, and a second surface opposite to the first surface and configured to cooperate with the hooking surface of the retaining collar.

According to an embodiment of the invention, the peripheral edge of the retaining collar is configured to delimit, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an insertion opening leading into the annular hooking housing, the at least one flexible retaining element being configured to extend through the insertion opening.

According to an embodiment of the invention, the insertion opening is oriented opposite the closure cap.

According to an embodiment of the invention, the tamper-proof ring comprises an annular portion connected to the fastening skirt by the frangible elements, the retaining collar having an outer diameter larger than the inner diameter of the annular portion.

The annular portion is advantageously configured to extend, when the closure cap is fastened to the neck portion and at least until a breakage of the frangible elements, around the retaining collar.

According to an embodiment of the invention, the peripheral edge of the retaining collar is located facing the inner surface of the annular portion at least until the breakage of the frangible elements.

According to an embodiment of the invention, the retaining collar is configured to exert, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, a radial force against the tamper-proof ring.

According to an embodiment of the invention, the neck portion comprises a stop surface against which the tamper-proof ring is capable of bearing after breakage of the frangible elements, the distance between the retaining collar in its initial position and the stop surface being larger than the width of the tamper-proof ring.

According to an embodiment of the invention, the at least one flexible retaining element comprises an end portion capable of being received within the annular hooking housing.

According to an embodiment of the invention, the at least one flexible retaining element extends from the annular portion of the tamper-proof ring.

According to an embodiment of the invention, the radial dimension of the retaining collar is larger than the axial dimension of the retaining collar. In other words, the width of the retaining collar is larger than the thickness of the retaining collar.

According to an embodiment of the invention, the retaining collar is configured such that, when the closure cap is fastened to the neck portion and at least until a breakage of the frangible elements, the peripheral edge of the retaining collar is shifted axially relative to the junction area between the retaining collar and the outer surface of the neck portion.

According to an embodiment of the invention, the at least one flexible retaining element is a flexible retaining flap.

According to an embodiment of the invention, the tamper-proof ring comprises a plurality of flexible retaining elements distributed over its inner circumference. Advantageously, the retaining elements are evenly distributed over the inner circumference of the tamper-proof ring.

According to an embodiment of the invention, the tamper-proof ring comprises at least one first drive element extending towards the fastening skirt, and the closure cap comprises at least one second drive element extending towards the tamper-proof ring, the at least one second drive element being configured to cooperate with the at least one first drive element, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, so as to displace the tamper-proof ring away from the fastening skirt and to form at least one opening check space between the fastening skirt and the tamper-proof ring.

According to an embodiment of the invention, the at least one first drive element extends from an upper edge of the annular portion of the tamper-proof ring, and the at least one second drive element extends from a lower edge of the fastening skirt.

According to an embodiment of the invention, the at least one first drive element comprises a first cam surface, and the at least one second drive element comprises a second cam surface configured to cooperate with the first cam surface so as to bias, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, the tamper-proof ring away from the fastening skirt.

According to an embodiment of the invention, the second cam surface is configured to cooperate with the first cam surface so as to bias, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, the annular portion of the tamper-proof ring away from the fastening skirt.

According to an embodiment of the invention, the second cam surface is substantially complementary to the first cam surface.

According to an embodiment of the invention, each of the at least one first drive element and the at least one second drive element has a wave- or ripple-like general shape.

According to an embodiment of the invention, the tamper-proof ring comprises a plurality of first drive elements distributed along the upper edge of the annular portion, and the closure cap comprises a plurality of second drive elements distributed along the lower edge of the fastening skirt.

According to an embodiment of the invention, the retaining collar is configured to extend at least partially in the at least one opening check space.

According to an embodiment of the invention, the closure cap comprises an annular sealing lip intended to cooperate with an inner surface of the neck portion.

According to an embodiment of the invention, the neck portion comprises at least one outer fastening element, and the fastening skirt comprises at least one inner fastening element configured to cooperate with the at least one outer fastening element provided on the neck portion.

According to an embodiment of the invention, the at least one outer fastening element is an outer thread.

According to an embodiment of the invention, the at least one inner fastening element is an inner thread.

According to an embodiment of the invention, the tamper-proof ring, and more specifically the annular portion, is located in the extension of the fastening skirt.

According to an embodiment of the invention, the at least one retaining element is deformable, for example elastically or plastically, between an initial position in which the at least one retaining element is oriented opposite the closure cap, and a hooking position in which the at least one retaining element is oriented towards the closure cap.

According to an embodiment of the invention, the neck element comprises a fastening portion secured to the neck portion and intended to be fastened on the receptacle.

According to an embodiment of the invention, the retaining collar is disposed between the at least one outer fastening element and the fastening portion.

According to an embodiment of the invention, the insertion opening is oriented towards the fastening portion.

According to an embodiment of the invention, the retaining collar substantially has, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an umbrella-like shape.

According to an embodiment of the invention, the closure cap and the tamper-proof ring are made by injection molding.

According to an embodiment of the invention, the neck portion includes an annular stop element, such as an annular stop rib, against which the at least one flexible retaining element is configured to abut during the first unscrewing of the closure cap. These arrangements allow limiting the displacement travel of the tamper-proof ring during the first unscrewing of the closure cap, which would be larger in the absence of such a stop element because of the flexibility of the retaining collar, and therefore ensuring sealing of the closure system at least until the breakage of the frangible elements.

According to an embodiment of the invention, the annular stop element is configured to extend into the annular hooking housing.

According to an embodiment of the invention, the stop element is disposed in the vicinity of the junction area between the retaining collar and the outer surface of the neck portion.

According to an embodiment of the invention, the stop element is formed on the outer surface of the neck portion.

BRIEF DESCRIPTION OF THE DRAWINGS

In any case, the invention will be better understood using the following description with reference to the appended schematic drawing showing, by way of non-limiting examples, two embodiments of this closure system.

FIG. 1 is a perspective view of a closure system according to a first embodiment of the invention.

FIG. 2 is a perspective view of the closure system of FIG. 1 in the assembled state.

FIG. 3 is a bottom perspective view of a closure cap and a tamper-proof ring of the closure system of FIG. 1.

FIG. 4 is a sectional perspective view of the closure system of FIG. 1 in the assembled state.

FIG. 5 is an enlarged view of a detail of FIG. 4.

FIG. 6 is a partially cutout perspective view, of the closure system of FIG. 1 showing the closure cap during unscrewing but before breakage of the frangible elements connecting the closure cap and the tamper-proof ring.

FIG. 7 is a partially cutout perspective view, of the closure system of FIG. 1 showing the closure cap during unscrewing and after breakage of the frangible elements.

FIG. 8 is a perspective view of the closure system of FIG. 1 showing the closure cap screwed back on a neck portion of the closure system.

FIG. 9 is a partially cutout perspective view of the closure system of FIG. 1 showing the tamper-proof ring in the same position as that shown in FIG. 8.

FIG. 10 is a perspective view of a closure system according to a second embodiment of the invention, showing the closure cap screwed back on a neck portion of the closure system.

DETAILED DESCRIPTION

FIGS. 1 to 9 show a closure system 2 for a receptacle, such as a packaging brick or a packaging carton, according to a first embodiment of the invention.

The closure system 2 comprises a neck element 3 intended to be fastened on the receptacle. Advantageously, the neck element 3 is integral, and is made of plastic material by injection molding.

As shown more particularly in FIGS. 1 and 4, the neck element 3 comprises a tubular neck portion 4 extending along an extension axis A, and a fastening portion 5 secured to the neck portion 4, and intended to be fastened, for example by ultrasonic welding, on the receptacle. According to the embodiment shown in the figures, the fastening portion 5 is annular and extends substantially radially relative to the extension axis A of the neck portion 4.

The neck portion 4 comprises, on its outer surface, an outer thread 6 and a retaining collar 7. The retaining collar 7 is annular and flexible, and is advantageously disposed between the outer thread 6 and the fastening portion 5. The retaining collar 7 comprises a first annular surface 8 facing the outer thread 6, and a second annular surface 9 opposite to the first annular surface 8 and facing the fastening portion 5.

More particularly, the retaining collar 7 is deformable, for example elastically or plastically, between an initial position, called rest position, (shown in FIG. 1) in which the retaining collar 7 extends radially relative to the extension axis A of the neck portion 4, and a retaining position (shown in FIG. 4) in which the retaining collar 7 is curved and the second annular surface 9 delimits an annular hooking housing 11.

As shown in FIG. 4, when the bearing collar 7 is in its retaining position, the peripheral edge 12 of the retaining collar 7 is shifted axially from the junction area between the retaining collar 7 and the outer surface of the neck portion 4, towards the fastening portion 5. Furthermore, when the bearing collar 7 is in its retaining position, the peripheral edge 12 delimits an insertion opening 13 leading into the hooking housing 11 and oriented towards the fastening portion 5.

The closure system 2 also comprises a closure cap 14 intended to be removably fastened on the neck portion 4. The closure cap 14 includes a closure wall 15 and a fastening skirt 16 extending from the closure wall 15. The fastening skirt 16 includes, on its inner surface, an inner thread 17 configured to cooperate with the outer thread 6 of the neck portion 4.

The closure cap 14 also includes an annular sealing lip 18 intended to cooperate with the inner surface of the neck portion 4.

The closure system 2 further comprises a tamper-proof ring 19 including an annular portion 21 located in the extension of the fastening skirt 16. The annular portion 21 is connected to the fastening skirt 16 by a plurality of frangible bridges 22 distributed along the upper edge of the annular portion 21. The closure cap 14, the tamper-proof ring 19 and the frangible bridges 22 are advantageously made simultaneously by injection molding.

According to the embodiment shown in the figures, the annular portion 21 has an inner diameter smaller than the outer diameter of the retaining collar 7.

The tamper-proof ring 19 also comprises a plurality of flexible retaining flaps 23 distributed circumferentially on the inner surface of the annular portion 21 of the tamper-proof ring 19, and configured to cooperate with the second annular surface 9 of the retaining collar 7. Each retaining flap 23 is deformable, for example elastically or plastically, between an initial position, called rest position, (see FIG. 3) in which each retaining flap 23 is oriented opposite the closure cap 14, and a hooking position (see FIG. 4) in which each retaining flap 23 is oriented towards the closure cap 14 and is capable of extending through the insertion opening 13 and being received at least partially in the hooking housing 11. More particularly, each retaining flap 23 is capable of hooking, in the use position, the retaining collar 7.

The tamper-proof ring 19 and the retaining collar 7 are configured such that, when the tamper-proof ring 19 is mounted on the neck portion 4, on the one hand, the annular portion 21 extends around the retaining collar 7, and deforms and holds the retaining collar 7 in its retaining position, and on the other hand, the retaining flaps 23 are deformed in their hooking position. Thus, under use conditions, the retaining collar 7 exerts a radial force against the tamper-proof ring 19, and more particularly against the inner surface of the annular portion 21.

According to the embodiment shown in the figures, the tamper-proof ring 19 further comprises at least one drive element 24 extending from an upper edge of the annular portion 21 and towards the fastening skirt 16, and the closure plug 14 further comprises at least one drive element 25 extending from a lower edge of the fastening skirt 16 and towards the tamper-proof ring 19.

According to the embodiment shown in the figures, the drive element 24 comprises a cam surface 26, and the drive element 25 comprises a cam surface 27 substantially complementary to the cam surface 25 and configured to cooperate with the latter, during the first screwing back of the closure cap 14 on the neck portion 4 after breakage of the frangible elements 22 and the first opening of the receptacle equipped with the closure system 2, so as to displace the annular portion 21 of the tamper-proof ring 19 away from the fastening skirt 16 and the retaining collar 7 (see FIG. 8).

According to the embodiment shown in the figures, each drive element 24, 25 has a wave- or ripple-like general shape.

It should be noted that the tamper-proof ring 19 might include a plurality of drive elements 24 distributed along the upper edge of the annular portion 21, and the closure cap 14 might include a plurality of drive elements 25 distributed along the lower edge of the fastening skirt 16.

The operation of the closure system 2 according to the invention will now be described, in particular, with reference to FIGS. 4 to 9.

As shown in FIG. 4, when the closure cap 14 is fastened on the neck portion 4 and the tamper-proof ring 19 is connected to the fastening skirt 16 by the frangible bridges 22, the retaining flaps 23 are distant from the hooking housing 11.

When a user drives in rotation the closure cap 14 in an unscrewing direction, the tamper-proof ring 19, which is connected to the closure cap 14, is driven by the closure cap 14 according to a helical movement towards the retaining collar 7 until the retaining flaps 23 penetrate into the hooking housing 11 and bear against the second annular surface 9, called hooking surface, of the retaining collar 7, as shown in FIG. 6.

Henceforth, any rotation of the closure cap 14 in the unscrewing direction causes a breakage of the frangible bridges 22, and therefore a separation of the tamper-proof ring 19 and the fastening skirt 14, as shown in FIG. 7. It should be noted that the tamper-proof ring 19 is held in its position shown in FIG. 7, because of the radial force exerted by the retaining collar 7 against the inner surface of the annular portion 21.

When the closure cap 14 is repositioned on the neck portion 4, and is driven in rotation in a screwing direction, the fastening skirt 16 progressively gets close to the tamper-proof ring 19 until the cam surface 27 of the drive element 25 cooperates with the cam surface 26 of the drive element 24 and displaces the tamper-proof ring 19 towards the fastening portion 5 and away from the fastening skirt 16. At the end of screwing of the closure cap 14, the tamper-proof ring 19 reaches the position shown in FIG. 8, and at least one opening check space 28 is formed between the fastening skirt 16 and the tamper-proof ring 19. The configuration of the drive elements 24, 25 thus allows checking easily any prior opening of a receptacle equipped with the closure system 2 according to the invention.

It should be noted that the tamper-proof ring 19 is held in its position shown in FIG. 8, because of the radial force exerted by the retaining collar 7 against the inner surface of the annular portion 21.

Advantageously, the neck portion 4 might further include an annular stop element 29, such as an annular stop rib, formed on the outer surface of the neck portion 4 and in the vicinity of the junction area between the retaining collar 7 and the outer surface of the neck portion 4, and configured to extend into the hooking housing 11. According to such an embodiment of the invention, the flexible retaining flaps 23, and more particularly the free ends of the flexible retaining flaps 23, are configured to abut against the annular stop element 29 during the first unscrewing of the closure cap 14. These arrangements allow limiting the displacement travel of the tamper-proof ring 19 during the first unscrewing of the closure cap 14, which would be larger in the absence of such a stop element because of the flexibility of the retaining collar 7, and thus ensuring sealing of the closure system, in particular at the level of the sealing lip 18, at least until the breakage of the frangible elements 22.

FIG. 10 shows an opening system 2 according to a second embodiment of the invention which differs from the first embodiment shown in FIGS. 1 to 9 essentially in that the retaining collar 7 is configured to be elastically deformed and extend at least partially between the fastening skirt 16 and the tamper-proof ring 19, during the first screwing back of the closure cap 14 on the neck portion 4 after breakage of the frangible elements 22, and more particularly after a displacement of the tamper-proof ring 19 away from the fastening skirt 16 induced by the cooperation of the cam surfaces 26, 27. More specifically, the retaining collar 7 is configured to extend into the at least one opening check space 28 during the first screwing back of the closure cap 14 on the neck portion 4. These arrangements allow ensuring an easy check of a prior opening of a receptacle equipped with the closure system 2 according to the second embodiment of the invention.

According to this second embodiment of the invention, the retaining collar 7 is configured to define the annular hooking housing 11 at least until the breakage of the frangible elements 22, and more particularly until the first screwing back of the closure cap 14 on the neck portion 4 after breakage of the frangible elements 22, and the tamper-proof ring 19 is configured to deform and hold the retaining collar 7 in its retaining position at least until the breakage of the frangible elements 22, and more particularly until the first screwing back of the closure cap 14 on the neck portion 4 after breakage of the frangible elements 22

After the initial screwing back of the closure cap 14 on the neck portion 4, a portion of the retaining collar 7 may possibly still be surrounded by the tamper-proof ring 19, and therefore exert a force on the tamper-proof ring 19 in order to hold it in position.

Of course, the invention is not limited to the sole embodiments of this closure system, described hereinabove by way of example, but it comprises on the contrary all variants thereof. 

1. A closure system for a receptacle, comprising: a neck element intended to be fastened on the receptacle, the neck element comprising a neck portion provided with a retaining collar which is flexible, a closure cap intended to be screwed on the neck portion, the closure cap including a closure wall and a fastening skirt, and a tamper-proof ring connected to the fastening skirt by a plurality of frangible elements, the tamper-proof ring comprising at least one flexible retaining element the neck portion and the tamper-proof ring being configured such that, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, the retaining collar defines an annular hooking housing, and the at least one flexible retaining element is configured to be at least partially received and be hooked into the annular hooking housing, characterized in that the retaining collar is configured to extend at least partially between the fastening skirt and the tamper-proof ring during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements.
 2. The closure system according to claim 1, wherein the retaining collar is deformable between an initial position in which the retaining collar extends substantially radially relative to an extension axis of the neck portion, and a retaining position in which the retaining collar is curved and delimits the annular hooking housing.
 3. The closure system according to claim 2, wherein the tamper-proof ring is configured to deform and hold the retaining collar in its retaining position at least until the breakage of the frangible elements.
 4. The closure system according to claim 1, wherein the tamper-proof ring is configured to extend around the retaining collar.
 5. The closure system according to claim 1, wherein the peripheral edge of the retaining collar delimits, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an insertion opening emerging in the annular hooking housing, the at least one flexible retaining element being configured to extend through the insertion opening.
 6. The closure system according to claim 1, wherein the tamper-proof ring comprises an annular portion connected to the fastening skirt by the frangible elements, the retaining collar having an outer diameter larger than the inner diameter of the annular portion.
 7. The closure system according to claim 1, wherein the retaining collar is configured to exert, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, a radial force against the tamper-proof ring.
 8. The closure system according to claim 1, wherein the tamper-proof ring comprises at least one first drive element extending towards the fastening skirt, and the closure cap comprises at least one second drive element extending towards the tamper-proof ring, the at least one second drive element being configured to cooperate with the at least one first drive element, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, so as to displace the tamper-proof ring away from the fastening skirt and to form at least one opening check space between the fastening skirt and the tamper-proof ring.
 9. The closure system according to claim 8, wherein the at least one first drive element comprises a first cam surface, and the at least one second drive element comprises a second cam surface configured to cooperate with the first cam surface so as to bias, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, the tamper-proof ring away from the fastening skirt.
 10. The closure system according to claim 1, wherein the neck portion includes an annular stop element against which the at least one flexible retaining element is configured to abut during the first unscrewing of the closure cap.
 11. The closure system according to claim 10, wherein the annular stop element is configured to extend into the annular hooking housing.
 12. The closure system according to claim 2, wherein the tamper-proof ring is configured to extend around the retaining collar.
 13. The closure system according to claim 3, wherein the tamper-proof ring is configured to extend around the retaining collar.
 14. The closure system according to claim 2, wherein the peripheral edge of the retaining collar delimits, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an insertion opening emerging in the annular hooking housing, the at least one flexible retaining element being configured to extend through the insertion opening.
 15. The closure system according to claim 3, wherein the peripheral edge of the retaining collar delimits, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an insertion opening emerging in the annular hooking housing, the at least one flexible retaining element being configured to extend through the insertion opening.
 16. The closure system according to claim 4, wherein the peripheral edge of the retaining collar delimits, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, an insertion opening emerging in the annular hooking housing, the at least one flexible retaining element being configured to extend through the insertion opening.
 17. The closure system according to claim 2, wherein the tamper-proof ring comprises an annular portion connected to the fastening skirt by the frangible elements, the retaining collar having an outer diameter larger than the inner diameter of the annular portion.
 18. The closure system according to claim 3, wherein the tamper-proof ring comprises an annular portion connected to the fastening skirt by the frangible elements, the retaining collar having an outer diameter larger than the inner diameter of the annular portion.
 19. The closure system according to claim 2, wherein the retaining collar is configured to exert, when the closure cap is fastened on the neck portion and at least until a breakage of the frangible elements, a radial force against the tamper-proof ring.
 20. The closure system according to claim 2, wherein the tamper-proof ring comprises at least one first drive element extending towards the fastening skirt, and the closure cap comprises at least one second drive element extending towards the tamper-proof ring, the at least one second drive element being configured to cooperate with the at least one first drive element, during the first screwing back of the closure cap on the neck portion after breakage of the frangible elements, so as to displace the tamper-proof ring away from the fastening skirt and to form at least one opening check space between the fastening skirt and the tamper-proof ring. 